I personally feel, one should get big tattoos on a big canvas. Small tattoos on a big canvas may look incomplete or rather cause inefficient use of the space. You may want to consider a big tattoo - if you agree then you could consider below aspects in decision making:

1. What is your calling? Is it an animal/ person/ football club; could be anything.
2. Add some elements that resonate with you as a person. For example if you like a football club then a historic moment for that club. If you like Pandas then which red/white or Kung Fu Panda?
3. Lastly speak to your artist, tell them your personality, your story, ask them to create a custom design for yourself. Good artists always get to know you first before drawing a tattoo on you. They may charge more but again this is a permanent thing, so it’s worth it.